The invention is generally directed to a method for equipping substrates with components, and more particularly to a method for positioning components on a substrate using equipping heads according to an actual time behavior program.
When equipping substrates, such as printed circuit boards with components, the components are taken from delivery units with the assistance of equipping heads and are positioned onto a predetermined position on the substrate by the equipping head. Optimally, many components per time unit should thereby be positioned on the substrates for a high equipping performance (equipped substrates per time unit).
International patent document no. WO 98/37744 discloses a means to achieve high equipping performance for manufacturing electrical assemblies that comprises two linear longitudinal guides in a central region that are in close proximity and parallel to one another. Carriages are correspondingly movable relative to the guides. These carriages comprise cantilevered transverse carriers for equipping heads that are directed away from one another toward the outside. Two separate processing locations result and are capable of being operated independently of one another. As a result, equipping performance of the device is enhanced.
For an even higher equipping performance, automatic equipping units are juxtaposed in the line. The different automatic equipping units each include different supplies of component types and can be specifically adapted for the respective component types. The different automatic equipping units exhibit a characteristic time behavior that includes the time required for picking up the components from the delivery units, transporting of the components to the desired position on the substrate, and placing of the components on the substrate. This time behavior is considered the same for all automatic equipping units of the same type in a first approximation. An equipping program that optimizes the paths of the equipping head in such a way that many components can optimally be placed in an optimally short time is produced with the assistance of this approximated time behavior.
This so-called fitting optimization, however, does not take the real time behavior of the automatic equipping unit into consideration. As a result, an incorrect work load of the individual equipping locations in the line occurs. Moreover, unpredictable interruptions can occur in the equipping line, such as a component that is not resupplied in time or, respectively, a conveyor that is down due to a malfunction, such as a malfunctioning equipping process or an entire station malfunction. In these cases, a standstill of the entire line occurs, even though only one station is faulty.
One object of the present invention is to provide a method for increasing the equipping performance or output when utilizing a plurality of equipping locations along a processing line. Another object of the present invention is to provide a method for increasing the equipping performance of an assembly line for placing components on a substrate by accounting for the real time behavior of automatic equipping units used along the assembly line equipping locations.
These and other objects, features and advantages are provided by a method of the invention that in one embodiment includes providing at least two equipping locations for equipping individual substrates with components. The components are respectively taken from delivery units by equipping heads and are placed onto substrates that are allocated to the at least two equipping locations. The equipping heads are controlled by a predetermined equipping program that includes allocation for each of the equipping locations and the components to be placed at each of the respective locations. A time for equipping a substrate is identified during the equipping process controlled by the predetermined program. The identified equipping time is compared to a predetermined time contained in the program and a time difference is calculated. The time difference is then compared to a predetermined time span that is used to generate an updated equipping program that allocates between each of the equipping locations and the components to be placed on the substrates. The updated equipping program accounts for the time difference. The equipping process for further substrates is then subsequently controlled according to the updated equipping program instead of the original predetermined equipping program.
According to the invention, the equipping program is monitored during operation, and an improved or updated equipping program is utilized, given the occurrence of bottle necks. As a result of the constant adaptation of the equipping program to the real time behavior of the equipping heads, the real time behavior of the machine is taken into consideration and an emergency operation of the line is enabled as well, given the occurrence of unpredicted faults.
In one embodiment of the method, the updated equipping program is checked anew in that the time actually required for the equipping process is measured. Whether the performance improvement that is initially only determined theoretically is in fact achieved is thereby checked. Given a known deviation of the theoretical from the real behavior of the equipping heads, one can achieve the goal of shortening the process time in fact, instead of the time becoming longer and longer in reality.
In one embodiment of the method, the real time behavior of the equipping locations is advantageously compared to the theoretically predetermined model. When the real time behavior deviates from the theoretical time behavior, an improved program is determined taking the realtime behavior into consideration and is utilized for the next equipping processes.
In one embodiment, the method can be utilized both for automatic equipping units wherein at least two equipping locations are provided as well as for lines wherein a plurality of automatic equipping units are arranged following one another.
For checking which components are placed by which machine, it is advantageously provided according to another embodiment of the invention that information about the components placed on the substrate at the respective equipping locations is stored.
The display of information for an operator according to a further embodiment advantageously assures that performance improvements that arise by re-equipping delivery units are also realized.